A fiber reinforced material using carbon fibers, aramid fibers, or the like as reinforcement fibers is widely used for structural materials used in aircrafts and automobiles and sport and general industrial applications such as tennis rackets, golf shafts, fishing rods, bicycles, and chassis utilizing its high specific strength and specific elastic modulus. As a method for producing a fiber reinforced material, a method of laying-up a plurality of prepregs, which are a sheet-like molding material formed by impregnating an uncured matrix resin in reinforcement fibers, and thereafter heating to cure the laid-up prepregs and a resin transfer molding method in which a liquid resin is poured into reinforcement fibers disposed in a mold and heating to cure the poured resin are used. Of these methods, the method of using prepregs has an advantage in that a high performance fiber reinforced material is easily obtained due to accurate control of the orientation of the reinforcement fibers and a high degree of freedom of design of laminate structures. As the matrix resin used for the prepreg, thermosetting resins are mainly used from the viewpoint of heat resistance and productivity. Of these thermosetting resins, epoxy resins are preferably used from the viewpoint of mechanical characteristics such as adhesion of the matrix resin to the reinforcement fibers. In recent years, the fiber reinforced materials have been required to improve various physical properties in order to meet the requirements of golf shafts, fishing rods, bicycles, automobile parts, industrial parts, and the like, which are required to have further reduced weights. In applications such as bicycle rims, automobile parts, industrial parts, and the like, for example, further improvement in heat resistance is required.
As the matrix resin used in the fiber reinforced material having excellent heat resistance, Patent Literature 1 describes an epoxy resin composition that can provide a fiber reinforced material having excellent elastic modulus and elongation as well as excellent heat resistance.
In addition, Patent Literature 2 describes an epoxy resin composition that can provide a cured epoxy resin having excellent heat resistance, elongation, and curability.
Furthermore, Patent Literature 3 describes a fiber reinforced material having excellent heat resistance, environmental resistance, and durability and high compression strength.